Laundry detergent compositions that both clean and soften fabric during a laundering process are known and have been developed and sold by laundry detergent manufacturers for many years. Typically, these laundry detergent compositions comprise components that are capable of providing a fabric-softening benefit to the laundered fabric; these fabric-softening components include clays and silicones.
The incorporation of clay into laundry detergent compositions to impart a fabric-softening benefit to the laundered fabric is described in the following references. A granular, built laundry detergent composition comprising a smectite clay that is capable of both cleaning and softening a fabric during a laundering process is described in U.S. Pat. No. 4,062,647 (Storm, T. D., and Nirschl, J. P.; The Procter & Gamble Company). A heavy duty fabric-softening detergent comprising bentonite clay agglomerates is described in GB 2 138 037 (Allen, E., Coutureau, M., and Dillarstone, A.; Colgate-Palmolive Company). Laundry detergent compositions containing fabric-softening clays of between 150 and 2,000 microns in size are described in U.S. Pat. No. 4,885,101 (Tai, H. T.; Lever Brothers Company).
The fabric-softening performance of clay-containing laundry detergent compositions is improved by the incorporation of a flocculant to the clay-containing laundry detergent composition. For example, a detergent composition comprising a smectite type clay and a polymeric clay-flocculating agent is described in EP 0 299 575 (Raemdonck, H., and Busch, A.; The Procter & Gamble Company).
The use of silicones to provide a fabric-softening benefit to laundered fabric during a laundering process is also known. U.S. Pat. No. 4,585,563 (Busch, A., and Kosmas, S.; The Procter & Gamble Company) describes that specific organo-functional polydialkylsiloxanes can advantageously be incorporated in granular detergents to provide remarkable benefits inclusive of through-the-wash softening and further textile handling improvements. U.S. Pat. No. 5,277,968 (Canivenc, E.; Rhone-Poulenc Chemie) describes a process for the conditioning of textile substrates to allegedly impart a pleasant feel and good hydrophobicity thereto, comprising treating such textile substances with an effective conditioning amount of a specific polydiorganosiloxane.
Detergent Manufacturers have attempted to incorporate both clay and silicone in the same laundry detergent composition. For example, siliconates were incorporated in clay-containing compositions to allegedly improve their dispensing performance. U.S. Pat. No. 4,419,250 (Allen, E., Dillarstone, R., and Reul, J. A.; Colgate-Palmolive Company) describes agglomerated bentonite particles that comprise a salt of a lower alkyl siliconic acid and/or a polymerization product(s) thereof. U.S. Pat. No. 4,421,657 (Allen, E., Dillarstone, R., and Reul, J. A.; Colgate-Palmolive Company) describes a particulate heavy-duty laundering and textile-softening composition comprising bentonite clay and a siliconate. U.S. Pat. No. 4,482,477 (Allen, E., Dillarstone, R., and Reul, J. A.; Colgate-Palmolive Company) describes a particulate built synthetic organic detergent composition which includes a dispensing assisting proportion of a siliconate and preferably bentonite as a fabric-softening agent. In another example, EP 0 163 352 (York, D. W.; The Procter & Gamble Company) describes the incorporation of silicone into a clay-containing laundry detergent composition in an attempt to control the excessive suds that are generated by the clay-containing laundry detergent composition during the laundering process. EP 0 381 487 (Biggin, I. S., and Cartwright, P. S.; BP Chemicals Limited) describes an aqueous based liquid detergent formulation comprising clay that is pre-treated with a barrier material such as a polysiloxane.
Detergent manufacturers have also attempted to incorporate a silicone, clay and a flocculant in a laundry detergent composition. For example, a fabric treatment composition comprising substituted polysiloxanes, softening clay and a clay flocculant is described in WO92/07927 (Marteleur, C. A. A. V. J., and Convents, A. C.; The Procter & Gamble Company).
More recently, fabric care compositions comprising an organophilic clay and functionalised oil are described in U.S. Pat. No. 6,656,901 B2 (Moorfield, D., and Whilton, N.; Unilever Home & Personal Care USA division of Conopco, Inc.). WO02/092748 (Instone, T. et al; Unilever PLC) describes a granular composition comprising an intimate blend of a non-ionic surfactant and a water-insoluble liquid, which may a silicone, and a granular carrier material, which may be a clay. WO03/055966 (Cocardo, D. M., et al; Hindustain Lever Limited) describes a fabric care composition comprising a solid carrier, which may be a clay, and an anti-wrinkle agent, which may be a silicone.
The Inventors have found that the optimal balance of fabric-softness performance to good physical property profile of particulate textile treatment compositions that comprise silicone, clay and anionic surfactant occurs when a specific anionic surfactant concentration gradient exists across the population of particles that make up the textile treatment composition.